From d694e0bb793ebd6b392e6ef6a3b0a59ae66cbc95 Mon Sep 17 00:00:00 2001
From: Fujii Masao
Date: Fri, 24 Jan 2020 20:42:52 +0900
Subject: Add pg_file_sync() to adminpack extension.

This function allows us to fsync the specified file or directory.
It's useful, for example, when we want to sync the file that
pg_file_write() writes out or that COPY TO exports the data into,
for durability.

Author: Fujii Masao
Reviewed-By: Julien Rouhaud, Arthur Zakirov, Michael Paquier, Atsushi Torikoshi
Discussion: https://www.postgresql.org/message-id/CAHGQGwGY8uzZ_k8dHRoW1zDcy1Z7=5GQ+So4ZkVy2u=nLsk=hA@mail.gmail.com
---
 doc/src/sgml/adminpack.sgml | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

(limited to 'doc/src')

diff --git a/doc/src/sgml/adminpack.sgml b/doc/src/sgml/adminpack.sgml
index 2655417366c..977073f7c8d 100644
--- a/doc/src/sgml/adminpack.sgml
+++ b/doc/src/sgml/adminpack.sgml
@@ -43,6 +43,13 @@
       Write, or append to, a text file
      </entry>
     </row>
+    <row>
+     <entry><function>pg_catalog.pg_file_sync(filename text)</function></entry>
+     <entry><type>void</type></entry>
+     <entry>
+      Flush a file or directory to disk
+     </entry>
+    </row>
     <row>
      <entry><function>pg_catalog.pg_file_rename(oldname text, newname text <optional>, archivename text</optional>)</function></entry>
      <entry><type>boolean</type></entry>
@@ -79,6 +86,18 @@
   Returns the number of bytes written.
  </para>
 
+ <indexterm>
+  <primary>pg_file_sync</primary>
+ </indexterm>
+ <para>
+  <function>pg_file_sync</function> fsyncs the specified file or directory
+  named by <parameter>filename</parameter>.  An error is thrown
+  on failure (e.g., the specified file is not present). Note that
+  <xref linkend="guc-data-sync-retry"/> has no effect on this function,
+  and therefore a PANIC-level error will not be raised even on failure to
+  flush database files.
+ </para>
+
  <indexterm>
   <primary>pg_file_rename</primary>
  </indexterm>
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